What i used to do in xfrog is i would take my genetica textures and just map them using x to y repeat mapping and my vegitation would always look good. I would use 1024 by 1024 size texture maps and atleast to me everything would look nice, even in close up view. Then using a bump map would add the needed depth for the bark and leaves or whatever else needs a bump map.
I figured sense terragen 2 does the whole x and y repeats for importing image data one can do the exact same thing here so UV i would think is not really needed.
